When you put your hand out the window of a moving car, you feel a force pushing against you called drag. This force opposes a moving vehicle, and it's part of the reason why your car naturally slows ...

Piling up: this image shows water flowing from left to right past a partially submerged sphere. A pile up of water is clearly seen to the immediate left of the sphere. (Courtesy: Harris Lab) ...

Drag (physics) For a solid object moving through a fluid or gas, drag is the sum of all the aerodynamic or hydrodynamic forces in the direction of the external fluid flow. It therefore acts to oppose ...